Development of polyelectrolyte multilayer thin film composite membrane for water desalination application F. Fadhillah a , S.M.J. Zaidi b, ⁎, Z. Khan c , M.M. Khaled d , F. Rahman e , P.T. Hammond f a Chemical Engineering Department of Al-Imam Muhammad Ibn Saud Islamic University, Riyadh, Saudi Arabia b Australian Institute for Bioengineering and Nanotechnology University of Queensland, Australia c Mechanical Engineering Department of King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia d Chemistry Department and Center of Excellence in Nanotechnology (CENT) of King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia e Center of Refining and Petrochemical, Research Institute of King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia f Department of Chemical Engineering, Massachusetts Institute of Technology, USA HIGHLIGHTS • The use of spin assisted layer by layer assembly (SA-LbL) for membrane preparation • Development of the SA-LbL protocol to fabricate thin film on polymeric substrate • PAH/PAA membrane fabricated using SA-LbL shows stability for long term use. • PAH/PAA membrane transport mechanism follows solution diffusion model. abstract article info Article history: Received 10 November 2012 Received in revised form 8 March 2013 Accepted 11 March 2013 Available online 10 April 2013 Keywords: Spin coating Layer-by-layer Reverse osmosis Membrane Polyelectrolyte Permeation Thin film composite membranes were fabricated via spin assisted layer by layer (SA-LbL) assembly by depos- iting alternate layers of poly(allyl amine hydrochloride) (PAH) and poly(acrylic acid) (PAA) on a polysulfone (PSF) ultrafiltration membrane as support. The suitability of these membranes for potential water purifica- tion applications was explored by testing the stability of the deposited thin films and their permeation char- acteristic using cross-flow permeation cell. Permeation test conducted at a pressure of 40 bar, temperature of 25 °C, pH of 6 and feed water concentration of 2000 ppm NaCl demonstrated that the PAH/PAA multilayer film deposited on polysulfone support remained stable and intact under long-term test conditions. The 120 bilayers of PAH/PAA membrane tested at the above condition showed flux of 15 L/m 2 .h and salt rejection of 65%. The membrane performance evaluation also revealed that SA-LbL PAH/PAA membrane follows the characteristics of the solution diffusion membrane. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Layer by layer (LbL) assembly has been widely used to fabricate ultrathin multilayer film for diverse applications since its re-discovery almost two decades ago [1,2]. The ability of this technique to provide conformal layer by layer coating of various functional materials on dif- ferent substrates has opened the possibility of its use in fabricating new type of thin film composite (TFC) membranes. Several pressure- driven separation membranes such as gas separation [3–6], pervapo- ration [7–9], nanofiltration [10–17] and reverse osmosis [18–22] have been fabricated by alternate deposition of anionic and cationic polymers via traditional dip LbL assembly. In such assembly, polyanion and polycation are deposited alternately on the substrate simply by dipping it alternately in both polyion solutions [2]. Although this technique is simple, environmentally friendly, and robust, long processing time, typically several minutes, required for deposition of single layer is con- sidered as the major drawback. Other drawbacks of the dip-LbL are its poor control on the film thickness and surface coverage of the deposited film at low number of layers. Two variants of LbL assembly namely, Spray LbL and Spin Assisted LbL (SA-LbL) assemblies were then introduced with the main aim of shortening the processing time, for example, Spray-LbL is 25 times faster than dip LbL [23] while SA-LbL requires few seconds only to de- posit single layer [24]. To the best of our knowledge, the use of SA-LbL assembly for fabricating pressure-driven membranes in water purifi- cation applications has not been investigated yet. As mentioned earlier, there have been several works done for dip-LbL membrane in water purification however very few studies have been conducted on membrane transport characteristic of such Desalination 318 (2013) 19–24 ⁎ Corresponding author. Tel.: +61 733464167. E-mail address: j.zaidi@uq.edu.au (S.M.J. Zaidi). 0011-9164/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.desal.2013.03.011 Contents lists available at SciVerse ScienceDirect Desalination journal homepage: www.elsevier.com/locate/desal